[Patent document 1] JP-2004-295472 A
There is conventionally known a technology to present a driver with information on driving operation support. In addition, in recent years, a large number of information items or signs relating to driving operation support have been presented to a driver.
However, although a driver is aware of the presented information items or signs, the driver feels botheration in the presentation of a large number of information items or signs. In addition, if the driver is presented with a large number of information items or signs when there is no time margin, the driver is confused. This may cause the driver to be impossible to recognize the information appropriately.
That is, the above mentioned technology may provide a disadvantage to degrade a comfortable ride for the driver.
Then, a measure is adopted to solve such a disadvantage as follows. For example, Patent document 1 discloses a vehicular alarm device which detects a direction of a sight line of a driver using a detector; determines based on the detected sight line whether the driver recognizes an obstacle; and prevents an alarm signal from outputting when it is determined that the driver recognized the obstacle, thereby eliminating a sense of interfere.
In this regard, however, even if the sight line of the driver is directed to the obstacle, the driver may not always recognize the obstacle. Thus, the driver may not move to action for collision prevention. In the vehicular alarm device in Patent document 1, the direction of the sight line is detectable, but it is not determinable whether the driver actually recognizes the obstacle. This may provide a possibility of canceling also an alarm signal which has a high necessity for output. That is, the vehicular alarm device in Patent document 1 poses a disadvantage that an accuracy of the alarm is not securable.
Further, in the vehicular alarm device in Patent document 1, it is necessary for a vehicle to carry a sight line detector to detect a sight line of a driver; however, a space to mount it is limited in the vehicle. It is thus not so easy to secure the space in the vehicle for installing the above sight line detector in addition to general in-vehicle apparatuses such as an in-vehicle navigation apparatus. This poses a problem that the implementation is not easy. Furthermore, mounting additionally such a sight line detector to detect only a direction of the sight line of the driver poses a problem to cause useless costs.